Method of making valve tappets



April 30, 1929. G. R. RICH 1,710,996

METHOD OF MAKING VALVE TAPPETS Filed May 14, 1928 l VG? Z1 07' (/2520 7? Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

GEORGE B. RICH, OF BATTLE CREEK, MICHIGAN, ASSIGNO'B, BY MESNE ASSIGNMENTS, TO WILCOX BICI-I COBYORATION, A CORPORATION OF MICHIGAN.

METHOD OF MAKING VALVE TAPPETS.

Application filed May 14, 1928. Serial N0. 277,561.

This invention relates to valve tappets and the method of making the same, and its principal object is to provide an improved valve tappet ot' the type embodying a hollow steel shank and a cast iron or white iron cam contacting surface. In the manufacture of such a ta pet-,the shank and head of the steel body are liored from end to end, and the (lilticulty which has been encountered in fusing cast iron to the head portion, is that of preventing the molten metal from flowing down through the hollow of the tappetbody. One of the objects of the present invention is to provide simple and efiicient means for closing the bore during the process of fusing the cast iron cam contacting surface portion to the body portion, whereby any of the molten metal is prevented from flowing into the bore of the tappet body. The invention further consists in the herein described method of producing a hollow stemmed tappet body provided with a cast iron cam contacting surface portion fused thereto.

The invention further consists in the several novel features hereinafter fully set forth and claimed.

The invention is clearly illustrated in the drawing accompanying this specification in which- I Figure l is a central. longitudinal section through a valve tappet embodying a simple term of the present invention;

Fig. 2 is a central longitudinal section through a blank from which the body portion is formed;

Fig. 3 is a central longitudinal section of the hollow bodyportion and showing the means for closing the opening therethrough durlng the fusing process; and

Fig. at is a plan. of the tappet body seen in Fig. 3. i

Referring to said drawing, which illustrates a simple embodiment of the present invention, the reference character 4 designates the body out the tappet, which comprises a hollow shank 5, internally threaded at one end, as at 6, and having a disk-like head portion 7 formed upon its other end. The shank 5 is bored out as at. 8 throughout the greater portion of its length, and the blank 5 (see- Fig. 2), from which the body portion is formed, is bored out as at 9 to provide a centering hole for the pilot of the die which is used in forging the head 7 of the body portion.

Seated upon and covering the bore 9 is a ball or other plug 10, which lies in a depression 11 formed in the head-7. Fused to the top of the head and to the ball or other plug 10 is a cast iron or white iron cam contacting surface portion 12. The head 7 is formed with a marginal rim 13 which provides a shallow depression 14 in which the cast iron or white iron cam contacting surface portion is received. The body portion 4 is made of steel, and, if desired, a steel ball 10 may be used to cover the bore 9. The cast iron portion 12 is fused to the top of the head 8 and to the ball ll), thereby forming to all intents and purpose an integral. structure composed of the steel body portion 4, the steel ball or plug 10 and the cast iron facing 12.

In the process of manufacturing valve tappets embodying the herein described invention, a suitable length of, steel rod 5 (see Fig, :2) is employed which is usually maclnned in an automatic machine, and the bores 8 and 9 are made therein, the'thread 6 cut on the wall of the bore 8, and the usual flattened portions made at the threaded end of the stem. This piece is heated to the required degree of temperature for forging the head, and is placed in a suitable lower head forn'iing die, with the stem portion submerged in water, and'the upper head "forming die is brought down upon the protruding end of the blank which is thereby spread outward and given the shape shown in Fig. 3.

The forging operation may be carried on in a suitable power hammer or press containing a die conforming to the shape of the upper side of the head. The die contains a pilot or centering pin which enters the bore 9 of the heated blank and in that manner centers the blank accurately with relation to the dies. Said pilot pin is of a shape corresponding to the shape of the recess 11 above the bore 9, as shown in Fig. 3. The blank being immersed in water-while hot, and while it is being forced, the stem portion becomes suitably hardened. After the body portion has been formed as described, the ball or other plug 10 is placed in the depression 11 and a bar or other piece of cast iron is placed in the depressed portion 14 of the head and fused to said head andball, or other plug, by an electric arc welding tool, or any other suitable tool, capable of supplyin sufiicient heat to properly fuse the severaf parts together. Finally the tappet is machined and finished as is well understood.

The cast iron becomes converted into white iron and forms a very hard surface portion for contacting with the cam of an internal combustion engine, as is well understood. The process of welding a cam contacting surface to the head of a valve tappet is more fully set forth and claimed in my Patents No. 1,606,181, dated November 9, 1926, for valve tappets, and No. 1,628,911, dated May 17, 1927, for improvements in composite metal articles of manufacture and process in the manufacture of the same.

During the fusing operation, in the present instance, the molten cast iron flows very readily, but the ball or ether plug acts as a closure for the bore 9 and effectively prevents the molten metal from flowing through the bore. The castiron, however, becomes fused to the ball and to the top of the head, thereby forming to all intents and purposes a composite metal integral structure.

More or less variation of the exact details of construction is possible without departing from the spirit of this invention. I desire, therefore, not to limit myself to the exact form of the construction shown and described, but intend, in the following claims, to point out all of the invention disclosed herein.

I claim as new, and desire to secure by Letters Patent:

1. The herein described method of making composite metal valve tappets which consists in boring and internally threading a steel rodlike blank, forging a disk-like head on one end of said blank, and sinking a cavity in the head portion, the cavity forming the continuation of said bore, closing said bore with a ball placed in the cavity and fusing cast iron to said head and ball. I

2. The herein described method of making composite metal valve tappets, which consists in boring a steel rod-like blank from end to end, forging one end of said blank into a disklike head, closing the bore at a point adjacent the head, depositing cast iron while in a state of fusion upon said head, and closure, and fusin to the head and closure the cast iron deposited thereon.

3. The herein described method of making composite metal valve tappets, which consists in boring a steel rod-like blank from end to end to form a bore having one part of relatively large diameter and one of small diameter, forging the end of said blank containing the small part of the bore into a disk-like head, enlarging part of the remainder of the small bore, closing the ren'iaining part of the small bore with a plug, depositlng cast iron while in a state ofvfusion upon said head and plug, and fusing to the head and plug the cast iron deposited thereon.

4. The herein described method of making composite metal valve tappets which consists in boring a steel rod-like blank from end to end to form a bore having one part of rota tively large diameter and one of smaller diameter, forging the end of the blank containing the small part of the bore into a disklike head, and simultaneously enlarging part of the small bore and forming a depression in the head, closing the enlarged part of the small bore with a ball, depositing cast iron While in a state of fusion in said depressed part of the head and upon the ball, and fusing to the head and ball the cast iron deposited thereon.

5. The herein described method of making composite metal valve tappets which consists in boring a steel rod-like blank from end to end to form a bore having one part of relatively large diameter and one of smaller diameter, forging the end of the blank containing the small part of the bore into a disklike head, and simultaneously enlarging part of the small bore and forming a depression in the head closing the enlarged part of the small bore with a ball, electrically depositing cast iron while in a state of fusion in said depressed part of the head and upon the ball, and fusing to the head and ball the cast iron deposited thereon.

6. The herein described method of making composite metal valve tappets which consists in boring a steel rod-like blank from end to end, heating the blank to forging temperature, forging one end of said blank into a disk-like head While the shank portion is submerged in Water, closing the here at a point adjacent the head, electrically depositing cast iron While in a state of fusion upon saidhead and closure, and fusing to the head and closure the cast iron deposited thereon.

GEORGE R. RICH. 

